1. Field of the Invention
The present general inventive concept relates to an apparatus to manufacture a semiconductor, and more particularly, to an apparatus to manufacture a semiconductor having a plasma-limiting device to vary a plasma region.
2. Description of the Related Art
Generally, in an etching process, which is performed when a semiconductor is manufactured, a reactive process gas is supplied to an inside of a reaction chamber in a vacuum state, and then high-frequency power is supplied to the inside of the reaction chamber so as to generate plasma discharge, thereby etching a film formed on a surface of a semiconductor substrate.
The above etching process is performed after a photosensitive pattern is formed on the surface of the semiconductor substrate. After the etching process is performed, a process for removing the unnecessary photosensitive film is performed. A semiconductor having a three-dimensional pattern is formed by repeating the above procedure. In a case in which the above multi-stage etching procedure is performed, volumes of plasma regions in first and second etching processes differ from each other, thereby supplying etching environments suitable for conditions of the first and second etching processes and increasing a removal rate of the photosensitive film in the photosensitive film-removing process.
U.S. Pat. No. 6,527,911 discloses a conventional plasma-limiting device for optimizing a necessary etching process by adjusting the volume of a plasma region. The conventional plasma-limiting device, disclosed by the above Patent, comprises inner plasma limit rings installed close to a semiconductor substrate for limiting the plasma region to an area having a small volume, and an outer plasma limit ring installed at the lower part of the semiconductor substrate for limiting the plasma region to an area having a large volume. When the plasma region in an etching chamber is to be decreased, the plasma region is limited by the inner plasma limit rings, and when the plasma region is to be increased, the plasma region is limited by the outer plasma limit ring.
However, the conventional plasma-limiting device separately comprises a driving device for driving the inner plasma limit rings and a driving device for driving the outer plasma limit ring, thereby having a complicated structure and high production costs.